Preset-voltage contact-making relay



Jan. 19, 1960 M. DEBREY 2,922,005

. PRESET-VOLTAGE CONTACT-MAKING RELAY Filed Oct. 18, 1957 2 Sheets-Sheet 1 50 IIIIIIIM v INVENTOR MICHAEL DEBREY ATTORNEYS Jan. 19, 1960 M. DEBREY 2,922,006

PRESET-VOLTAGE CONTACT-MAKING RELAY Filed Oct. 18, 1957 2 Sheets-Sheet 2 FIG. 2

1 J I I I FIG. 5

I i 30 7 FIG. 3 all,

, FIG 6 Q7?- 7; 77 INVENTOR w 1% MICHAEL DEBREY M l 7 BY /m. M) 6 ATTORNEY5 United States Patent PRESET-VOLTAGE CONTACT-MAKING RELAY Michael Debrey, Springfield, 111. Application October 18, 1957, Serial No. 691,030

8 Claims. (Cl. 200-94) This invention relates to improvements in electromagnets and switches operated thereby, and more particularly to a general purpose preset-voltage contact-making switch or relay. While the invention has many uses, it is especially useful as a contact making voltmeter since the contact making or breaking can be arranged to take place over a large range of voltages.

One object of the invention is to provide an improved contact making instrument employing an electromagnet of the solenoid type in which the core or floating element is moved upward by magnetic pull and downward by gravity without the use of springs.

Another object is to provide in an electromagnetically operated switch of the above character an improved floating core structure and improved means for suspending it.

Another object is to provide an improved coil mounting with improved magnetic shielding that provides effective cooling of the coil and its core.

Another object is to provide a contact making voltmeter or the like of the above character which will operate a with extreme accuracy when the voltage for which the instrument may be set is reached.

v With the above and other objects and advantages in view, the invention resides in the novel combinations and arrangements of parts and the novel features of construction hereinafter described and claimed, and illustrated in the accompanying drawings which show the present preferred embodiment of the invention.

In the drawings: I

Fig. 1 is a front elevation, with parts broken away and in section, of the preferred embodiment of the invention;

Fig. 2 is a top plan view of the instrument shown in Fig. 1;

Fig. 3 is a bottom plan view;

Fig. 4 is a detail perspective view of a bracket used in supporting one switch contact lever from another;

Fig. 5-is aside view of the core or floating element;

Fig. 6 is a transverse section on the line 6-6 in Fig. 5;

Fig. 7 is a detail view showing the pivotal mounting for the lower core mounting lever, the arrow on the line 7-7 in Fig.3 indicating the direction from which the mounting is viewed.

Referring more in detail to the drawings the numeral 10 denotes an upright support in the form of a suitably shaped panel of insulating material from the front of which projects upper and lower plates 11 and 12, also of insulating material, connected by a plurality of upright spacing members 13. These parts provide an open frame for supporting the parts of an electromagnetically operated switch mechanism. This frame is fastened to the upright panel by at least two bracket members fastened to the undersides of the horizontal plates 11 and 12 by screws 16 and having reduced and screw threaded rear ends projecting through the upright plate and held by nuts, as seen in Figs. 1 and 3. Preferably four of the metal spacing members or posts 13 are used and they are equally spaced between the opposed faces of the plates 11 and 12 and fastened thereto by screws 17. One of these screws, designated 17' in Fig. 1, may take the place of one of the screws 16 to fasten the lower bracket bolt 15 to the lower plate 12, as seen in Fig. '1.

The numeral 20 denotes the solenoid coil wound on the major portion of a cylindrical tube 21 of insulating material and disposed between the plates 11 and 12. The projecting ends of the spool or tube 21 are seated in circular openings 22 formed in the plates 11 and 12 and centrally in the space surrounded by four spacers 13. The ends of the wire coil 20 may be connected to binding posts 23 on the panel 10 and to the latter are connected the conductors 24 of a circuit from any source of direct or alternating current. A variable resistor 25 with a sliding contact may be included in the power line 24 as indicated in 'Fig. 1.

The voltage coil 20 actuates an upright core 30 of special construction which is freely movable in the tube 21 without contacting the inner surface of the latter. This floating element of the solenoid is of cylindrical shape and is made of soft solid ferrous metal, preferably a very soft iron. The core is preferably formed with a central bore 30' and in its ends are screwed or otherwise fastened upper and lower stems 31 and 32 by means of which it is supported so that it cannot contact with the inner surface of the tube. The cylindrical body of the core is formed with an annular series of straight longitudinal grooves or channels 33 which extend from end to end of the core and which have a depth of a little more than one-half the radius of the core, as will be seenupon reference to Figs. 5 and 6. These ventilating grooves, preferably six or more in number, are equally spaced around the circumference of -the core, and one of them, designated 34 in Fig. 6, is deeper and opens into the bore 30' of the core to prevent the formation of eddy currents.

In order to support the core and maintain it at all times out of contact with the tube 21 and substantially concentric with the coil 20, its stems 31 and 32 are pivotally connected to upper and lower levers 35 and 36. The upper lever 35 is disposed horizontally above the plate 11 and is pivotally mounted between its ends on said plate so the lever can have no lateral shifting movement. That is accomplished by fixing the lever at the center of a cylindrical bearing sleeve 37 disposed between spaced upright brackets 38 on the plate 11 and supporting a pivot-pin 39 on which the sleeve 37 rotates. This axis 39 for the lever may be a bolt with a head engaged with one bracket 38 and a threaded end screwed into the other, as seen in Fig. 2. The brackets 38 have reduced threaded ends projecting through holes in the plate 11 and fastened by nuts 40. The long inner arm of the lever 35 is disposed over the axis of the core and has a vertical opening to receive the reduced end of the stem 31, the latter being mounted on a pivot pin 41 to provide a pivotal connection between that lever and the core. A similar pivotal connection, as shown at 42 in Fig. 1, is provided between the reduced lower end of stem 32 and the lower lever 36. The latter is disposed horizontally beneath the plate 12 and it extends away from the axis of the core in a direction opposite to that of the lever 35. While the two levers may have the same eifective length, that is not necessary because of the limited vertical movement of the core. The pivotal mounting of the lower lever is similar to that of the upper end so that there can be no lateral movement. As shown in Figs. 1, 3 and 7, the outer end of the lever is fixed to the center of a sleeve 43 rotatable on a pivot pin or bolt 44 in spaced brackets 45. As seen in Fig. 7, the brackets 45, while similar to the brackets 38, are fastened by reduced riveted ends to a forwardly and rearwardly extending bar 46 which is fastened to the bottom of the plate 12 by a pair of screws 'metal lever 35 and adjustably fixed by a nut 52.

, lever.

V Themoveme'nt of the core30 operates. a, switch mechanlsm to close and openan electric circuit 50 of any desired character, and the core s'upportinglever 35 -isi'us ed as the movable contact-carrying member of. they switch. The movable contact 51 may be threaded pin screwed into an intermediate portion of the long arm of the coacting contact 53 is carried by an intermediate portion of a second metal lever 54 disposed vertically above the lever 35' This relatively stationary contact 53 may be a threaded rod disposed in an opening in the lever and adjustably fixed by nuts 55 above and below the The lever 54 has its outer end fulcrumed on an L-shaped bracket 59 carried by the short arm 60 of the lever, as seen in Fig. l. The metal bracket 59, shown in Fig. 4, has a short apertured arm 61 adapted to be clamped on the end of arm 60 in insulated relation The 1 thereto, and a long upstanding armf62 against which the lever 54 is pivoted by a screw '6 3 threaded into an aperture in arm 62. The lever end 60 passes through an insulating bushing in an aperture 64. in short arm of the bracket and insulating washers are provided on each side of the bracket, as seen in Fig. 1, so that when a nut 65 on the threaded extremity of the arm 60 is tightened,

wire coil 69 to a terminal clip 70 beneath the nut 65,

on the lever 35. I

The circuit 50 includes a source of power 71 usually of any safe voltage and some electrically operated element 72. The latter is shown as an electric alarm hell but it may be a relay of a voltage regulator or any instrument that will register or signal an abnormal voltage either high or low. As shown in Fig. l the arrangement is such that the switch contacts will close on the highest limit voltage for which the device is set to operate or make contact. Y s p The upper lever 54 of the switch is limited in itsdownward movement by a stop 75 mounted on the panel 11 and disposed beneath the inner end of the lever. This stop is preferably in the formof a roller on which the lever has a limited sliding movement as it swings on its pivot 63 carried by the short outer arm of the lever 35. The roller 75 is mounted on a pivot pin 76 at the front end of a horizontal bracket arm 77. The reduced and threaded rear end of this bracket is fastened'in a hole in the plate 10 by a nut, as seen in Fig. 2. The

' roller sets the limit for contact making and breaking and the lever is normally held in engagement with the roller by a very weak coil spring 78 connected between the two levers 35 and 54 but insulated therefrom. 'One end of the spring is anchored to a screw 75 threaded into a plug or bushing 79 of insulating material set in the lever 35, as seen in Fig. l. The other end of the spring is attached to a flexible strand 80 of insulating material which extends through an inclined hole in the lever 54 and has itso-ther end attached to a screw 81 in the upper'side of that lever. The function of the spring 78 is to prevent chattering or humming of the contacts 51 and 53 and to cause effective engagement of the contacts without extreme upward pressure on the contact 51 by reason of magnetic force.

In order to prevent the operation of the instrument from being afiected by outside 'forces such as the location of a magnetic substance in proximity to the coil, I provide effective magnetic shieldingwhich will not interfere with the proper cooling of the coil; This is accomf A coil of flexible wire 67 elecplished by surrounding the coil with an annular series of spaced upright rods 84 of'steel or other magnetic material. These'rods are disposed between the plates 11 and 12 and have their lower ends projecting'into sockets 85 in the lower plate while their upper ends project through holes 86 in the upper plate. The rods are held in place by a circular plate or disk 87 of steel or the like engaged with the upper' ends of the rods and fastened to. the top of the plate 11 in spaced relation therewith bya' plurality of screws 88. This disk also serves to shield the coil with respect to the steel and other metal parts. forming portions of the switch mechanism. This magneticshielding disk has a central hole through which the core stem 31 extends, and it is formed with a radial slot 89 to prevent eddy currents. The shielding rods or bars 84 may be in a continuous circular series and equally spaced from each other, but as shown in Fig, 2 they are disposed in four groups with preferably eleven rods in each group, the adjacent groups being slight- 1y spaced One important advantage of using an annular series of removable" rods 84 as the shielding means, is

that when the relay is calibrated for a given operation,

one or more of the rods may be added or removed until the required operation is attained. 'In this way a variable magnetie shielding is obtained.

' The uses and operation of my improved magnetically operated relay will be apparent from the foregoing detailed description. The core or floating element is moved upwardly by magnetic pulland downwardly by gravity without the use of springsgand because of the construction of the core and its mounting, the magnetic shielding, and the provision for cooling the coil and core, the instrument will operate with accuracy over a wide, voltage range and cause the switch contacts to engage at thepresent voltage. I 7

From the foregoing, taken'in connection with the accompanying drawing, it will be seen that novel and advantageous provisionhas been made forcarrying out the objects of the invention, and while preferences have been disclosed, attention is invited to the possibility of making variations within the scope of the invention as "claimed.

I claim: 1. In a preset-voltage contact-making relay having an upright tubular voltage coil,'supporting means mounting second lever on the short arm of said first lever in electrically insulated relation therewith, coacting contacts on the two levers, means pivotally connecting the long arm of said' first lever to the upper end of said core, and a stationary support carrying a stop disposed under the free end of said second lever. I

2. In a preset-voltage contact-making relay having an upright tubular voltage coil, supporting means mounting said coil and including an upper insulating platedisposed above said coil, and an armature core movable in said coil, a first switch lever pivotally mounted between its ends on top of said upper plate,said lever having a long arm carrying a switch contact and'a short arm, an upright conducting bracket on said short arm and electrically insulated from said lever, a second switch lever carrying a 'coacting switch contact and disposed above said first lever, means pivotally mounting one end of said second lever on said bracket, a stationary support: carrying a roller disposed under the free end of said second-lever, a coil spring connecting an intermediate portion of said second lever to the long arm of said first lever and electrically insulated from both of said levers, and means pivotally connecting the long arm of said first lever to the upper end of said core.

3. The combination of claim 2 in whichsaid supporting means including a lower insulating plate disposed beneath said coil and in which said first lever is disposed radially with respect to the longitudinal axis of said core, together with a third lever pivotally mounted at one end on the bottom of said lower plate, said third lever being also disposed radially with respect to the longitudinal axis of said core and extending in a direction opposite to that of said first lever, and means pivotally connecting the free end of said third lever to the lower end of said core.

4. The combination of claim 3 in which the pivotal mounting of each of said first and third levers includes a sleeve to the intermediate portion of which one of the levers is fixed, and a pivot pin extending through the sleeve and about which the associated lever swings.

5. The combination of claim 2 in which said supporting means includes a lower insulating plate disposed beneath said coil, together with means for magnetically shielding said coil, the shielding means comprising laterally spaced upright rods of magnetizable metal arranged in an annular series around and spaced from said coil, said rods having their lower ends engaged with seats in said lower plate and their upper ends extending through holes in said upper plate and terminating above the top of the latter, a disk of magnetizable metal disposed above said coil and between said first lever and said upper plate and engaged with the projecting upper ends of said rods, and screw threaded means between said disk and said upper plate to fasten said rods and hold said disk in spaced relation to said upper plate.

6. The combination of claim 2 in which said supporting means includes a lower insulating plate disposed beneath said coil, together with a third lever pivotally mounted at one end on the bottom of said lower plate and having its other end pivotally connected to the lower end of said core, and means for magnetically shielding said coil comprising an annular series of laterally spaced upright rods of magnetizable metal surrounding said coil in spaced relation therewith and held between said upper and lower plates, and a disk of magnetizable metal disposed above said coil and held between said first lever and said upper plate in spaced relation to both.

7. In a preset-voltage contact-making relay having a support including upper and lower insulating plates, an upright tubular voltage coil disposed between said plates and an armature core movable in said coil, 2 first switch lever pivotally mounted between its ends on the top of said upper plate, said lever having long and short arms, a second switch lever disposed above said first lever, means pivotally mounting one end of said second lever on the short arm of said first lever in electrically insulated relation therewith, coacting electrical contacts one mounted on an intermediate portion of said second lever and the other on an intermediate portion of the long arm of said first lever, means pivotally connecting the end of the long arm of said first lever to the upper end of said core, a third lever pivotally mounted atone end on the bottom of said lower plate, means pivotally connecting the other end of said third lever to the lower end of said core, a stop carried by said support and disposed under the free end of said second lever, and spring means associated with and electrically insulated from said first and second levers urging said second lever toward said stop.

8. The combination of claim 7 in which the pivotal mounting of each of said first and third levers includes a sleeve to the intermediate portion of which one of these levers is fixed and a pivot pin extending through the sleeve and about which the associated lever swings.

References Cited in the file of this patent UNITED STATES PATENTS 1,573,095 Saklatwalla et al Feb. 16, 1926 1,758,456 Menicocci May 13, 1930 1,987,555 Foster Jan. 8, 1935 2,165,887 Debrey July 11, 1939 2,207,082 Wetzel July 9, 1940 2,234,110 Debrey Mar. 4, 1941 2,539,547 Mossman et al Ian. 30, 1951 

